Injection molding machines are commonly used to mold plastic objects. An injection molding machine molds plastic objects by repeatedly performing a mold cycle. During each mold cycle, the machine injects molten plastic into a mold, cools the plastic, opens the mold, ejects the molded object, closes the mold, and recovers for the next cycle. Various injection molding machines include variations of this mold cycle, as known in the art. A controller, which is programmed with the mold cycle, controls the machine according to the mold cycle.
Injection molds are designed to mold particular objects from particular plastics at particular pressures. Injection molding machines are designed to accept a range of mold sizes and to inject plastic within a range of injection pressures. A molding machine and its mold can be designed to last for many mold cycles.
It can be challenging to make changes to an injection molding machine. Since a molded object is planned for a particular end use, it is usually not feasible to significantly change its plastic material. Since a mold is manufactured with particular geometries shaped in metal, it is usually not possible to significantly change its configuration. And since an injection molding machine is designed and built as a complete, integrated unit, it is usually impractical to change its set-up.
Thus, many molding machines operate with substantially the same material, mold, and mold cycle, for the life of the mold—sometimes many years. On the one hand, operating over a long life allows this equipment to pay back its large capital expense. On the other hand, operating over a long life without significant improvements means that any inefficiencies in the mold cycle accumulate more costs over time.